Process for removing individual metal sheets from a stack and device for carrying out the process

Abstract

Two sheets (10,14) are removed simultaneously from the sheet stack (1). While one sheet (10) is already in the transfer position, from which it is introduced into the conveyor line by two feed rolls (7,8), a first suction element (20) seizes the next sheet (14) from the stack (1). This sheet is moved along the curve a into the now vacated transfer position. A second suction element (30), which is no longer needed to hold the first sheet (10) there, moves to the stack (1) to seize the next sheet (15) and bring it to the transfer position, while the first suction element moves back to the stack. In this way, destacking can proceed at a faster rate than hitherto.

We claim: 
     
       1. Process for destacking individual metal sheets from a stack by means of at least two destacking members which seize the sheets from the stack, and for feeding the sheets into a conveyor line, characterized in that one destacking member seizes one metal sheet different from the other of the destacking members from the stack and without releasing the metal sheet holds the metal sheet in a position generally parallel to the position of the metal sheet in the stack during movement from the stack to a pair of feed rollers without interference or cooperation from other members or seized sheets, the feed rollers being positioned at a transfer position for transfer to the conveyor; and at least two sheets are engaged in the destacking process at any one time so that while one sheet is being positioned for transfer to the conveyor line, a destacking member is being moved to bring the next sheet to the feed rollers. 
     
     
       2. Process according to claim 1, characterized in that the destacking member positions each sheet on a table at the transfer position. 
     
     
       3. Process according to claim 1, characterized in that two destacking members are provided, and while one destacking member is positioning a sheet the other destacking member is being moved to ready the next sheet. 
     
     
       4. Process according to claim 1, characterized in that each destacking member executes a movement parallel with the plane of the sheet in the transfer position and a movement transverse to the said plane, so that each destacking member circumvents the sheet. 
     
     
       5. Process according to claim 1, characterized in that the stack has a top end and a bottom end; and the sheets are removed from one end of the stack. 
     
     
       6. A process for destacking according to claim 1, wherein the steps performed by each destacking member of seizing a metal sheet, and holding the metal sheet during movement from the stack to the transfer position are carried out in a can welding machine. 
     
     
       7. Device for destacking individual metal sheets from a stack and feeding the sheets into a conveyor line, characterized by at least two destacking members, each of the destacking members being operable to individually seize one metal sheet different from the other destacking members from the stack, and without releasing the sheet or rotating the sheet after being seized from the stack and being movable with the sheet without interference from any other member or seized sheet from the stack directly to a transfer position; and a transfer arrangement comprising a pair of feed rollers positioned at the transfer position to transfer the positioned sheets into the conveyor line. 
     
     
       8. Device according to claim 7, characterized in that has destacking member has controllable suction elements to releasably grip the sheet, and a table (16) is provided for supporting the sheet at the transfer position. 
     
     
       9. Device according to claim 7, characterized in that two destacking members (20,30) are provided, each provided with controllable suction elements to releasably grip a sheet. 
     
     
       10. Device according to claim 7, characterized in that the transfer arrangement is mounted in a can welding machine.